The present invention relates to a shock absorber for a vehicle with a flexible suspension. The shock absorber has two members which are associated with one another in a deformable manner in the deformation direction of the vehicle suspension. In the operation position, the two members of the shock absorber are respectively fixed to a suspended part and to an unsuspended part of the vehicle.
Numerous shock absorber constructions of the above type are known and in particular telescopic hydraulic shock absorbers which comprise a damping piston slidingly mounted in a cylinder containing a liquid. This cylinder has a first end connected to one of the above-mentioned parts of the vehicle and the damping piston is fixed to a sliding rod traversing the other end of the cylinder and fixed to the other part of the vehicle. In the special case of so-called by-tube shock absorbers, the cylinder is placed within a tubular body with which it communicates.
Most of the known shock absorbers of the type defined hereinbefore give acceptable results under standard conditions of use of the vehicles for which they are provided. However, particularly in the case of vehicles with a high loading capacity and whose suspension is very deformable, the effectiveness of damping or shock absorption is often impaired with known shock absorbers.
Thus, in the case of a load differing from the normal average load, the relative position of the two members of the shock absorber at rest can differ greatly from the position provided by the designer. Thus, the shock absorber functions abnormally and in particular there is a pronounced inadequacy of the use of travel in one operating direction.
The disadvantage of the principle defined hereinbefore linked with the load variations of the vehicle compared with the average load provided is increased if the possible limit values of the total weight of the vehicle in operation have a significant variation. Moreover, for each shock absorber of the vehicle, a local variation in the load supported by the corresponding part of the suspension tends to compromise the efficiency of shock absorption.
Thus, the efficiency of the system of vehicle shock absorbers is dependent on the flexibility of the suspension, which can be greatly deformed in the inoperative position compared with an average position provided by the design for each shock absorber. The above-mentioned deformation of the suspension and of each shock absorber of the vehicle in the inoperative position results both from load variations and variations in the centering of the vehicle.